1. Field of the Invention
The present invention relates to a wireless communication system. More particularly, the present invention relates to a multi-hop wireless communication system which performs multi-hop communication via a relay station.
2. Description of Related Art
Multi-hop communication is used to improve communication coverage and system capacity. Specifically, a relay station is a basic component for multi-hop communication in a cellular system. However, there is more neighbor information in multi-hop communication systems having relay stations than in communication networks having only base stations since multi-hop communication systems having relay stations include more neighbors than communication networks having only base stations. Specifically, the number of neighbors associated with a particular node increases since the relay stations in the communication network are included in the number of neighbors. Also, neighbor information increases since the number of neighbors increases. Accordingly, the number of neighbors in a neighbor list increases.
The increase in the number of neighbors causes a huge increase in overhead when distributing the neighbor information. Also, the increase in the number of neighbors increases the time spent in performing a scan process for the hand-off in a mobile station.
Accordingly, it is important to decrease the number of neighbors included in a neighbor list of a multi-hop communication system where the relay stations are added. However, when the number of neighbors included in the neighbor list is not efficiently reduced, necessary neighbors may be deleted from the neighbor list.
Accordingly, there is a need for a new method of providing neighbor information. In the new method of providing neighbor information, from a mobile station's point of view, electric power and effort required to scan for neighbors, as well as handover delay, is reduced. Also, from a system's point of view, the overhead, which is necessary for distributing neighbor information, is reduced and necessary neighbors are prevented from being deleted.